# 子函数中发生异常，往上抛，上层函数得异常，没有try，继续往上抛，直到遇到try
def demo1():
    num = int(input("输入整数："))
    print("I am demo1")
    return num

def demo2():
    num2 = demo1()
    print("I am demo2")
    return num2

#
# try:
print(demo2())
# except Exception as result:
#     print("未知错误 %s" % result)
